One such simple and cost-effective pump which is both functionally reliable and has a long service life is advantageously used as a lubricating pump in two-stroke engines especially two-stroke injection engines for portable handheld work apparatus such as motor-driven chain saws. The oil pump is used to provide separate lubrication to supply the piston path, the bearing it catera with lubricating oil. Such a pump is also advantageous for supplying lubricating oil for the saw chain of a motor-driven chain saw.
A connection between the suction connection and the pressure connection of the pump and other channels for conducting the lubricating oil must be provided when building a pump of this kind into the housing of a work apparatus. The connection must be tight with respect to the medium under pressure. For this purpose, appropriate sealing rings are mounted in the housing or on the stator of the pump which is both time and work intensive.